Self-loading trailers for cylindrical hay bales and other large or bulky commodities are generally well known and have been used for many years. In this regard, U.S. Pat. Nos. 3,938,682 and 4,089,425 (the entire content of each such patent being incorporated expressly hereinto by reference) each disclose self-loading trailers which are believed to be representative of the state of this art.
As can be seen from these prior-issued U.S. Patents, the conventional hay bale transport trailer necessarily includes an electrical or hydraulic actuated braking system. The electrical or hydraulic braking system is provided so as to halt rearward movement of the trailer during a bale loading/unloading operation and thereby allow the trailer to articulate at the axle joining the forward trailer hitch frame and the rearward bale cradle frame. The electrical or hydraulic braking system of these prior art bale transport trailers therefore must be interconnected to the pulling vehicle's electrical or hydraulic systems, respectively, thereby adding costs to enable a vehicle to be retrofitted for purpose of pulling the hay bale transport trailer. Furthermore, the braking systems associated these prior art transport trailers are susceptible to wear over time thereby requiring additional maintenance costs for the trailer operator/owner.
It will also be appreciated by those in the art that the weight of the hay bale when located in the cradle frame exerts a substantial load on the articulation axle joining the cradle frame to the hitch frame of the trailer. Over time, therefore, conventional trailers may experience structural failure of the articulation. As an attempt to overcome this problem, the trailers disclosed in the above-cited '682 and '425 each employ a rigid load-beating member. For example, as seen in the '682 patent, a rigid limiting strap is provided which joins the rearward cradle frame to the forward hitch frame. In the '425 patent, the cradle frame is provided with a cross-bar against which rearward leg sections of the hitch frame bear.
Although the prior art hay bale transport trailers are satisfactory for their intended purpose, some improvements are still desired. For example, it would especially be desirable if a hay bale transport trailer could be provided with a braking system that did not need to be operatively interconnected to the pulling vehicle's electrical and/or hydraulic systems. It would likewise be desirable if a simplified structure could be provided which transfers the load from the cradle frame to the hitch frame (i.e., so that the articulating axle does not bear the entire load of the transported hay bale). It is therefore towards obtaining these desirable attributes of hay bale transport trailers that the present invention is directed.